Geez, the fun just continues! I was driving the car and the check engine indicator, the one signaling an issue with the emissions control just went on. So I get home turn it off, and go in the house. I go back out open my trunk lid, and the passenger mirror starts going down, just like I have it in reverse. I stop, the mirror stops, I open the rest of the way, the darn thing completes its cycle. I close the trunk, it returns to its original spot.

Didn't I see this in a Twilight Zone episode? Should I look and see if there is a "gremlin" crawling around my "Panzerwagen"?

Dang, I wish I was Paul!

 

What year and how close do you live to the sun? LOL

 

I just don't know what your problem is....do you have access to the ross-tech softwar or know somebody in Indy that does? I have done more research....but am still blank.

But with your light showing up, the car might of thrown a code (or you probably have codes in such modules as the alarm system), so really the next thing to do is to pull the codes.

If you don't have the ross-tech software, I would buy it, it will save you a lot of money! Get the Bently manual too!

pw

 

You say you have all these problems, when the thing goes in reverse you get the lights on the dash, sometimes you do, sometimes you don't, you pulled some fuses, it worked, it didn't, you put the fuse back in, it did the same thing again.

Now the mirror dips when you open and close the trunk lid. What the heck is with that? Yes, that is the clue I'm thinking off.

First of all, is the RH mirror selected so when you go into reverse, it dips the mirror? I imagine so. If not, my theory is flawed.

If so, this is actuated by F125, which is the multi-function transmission range (TR) switch. When you put the car is gear, there is a linkage to the side of the tranny, but it doesn't actually do anything in the tranny, it just operates a six wafer switch on the side of the tranny.

When in reverse, it makes two contacts, one that tells the transmission control unit to energize the correct hydraulic valves to shift the tranny into reverse, and another to energize the reverse lights and tell the mirror memory control module to dip the right hand mirror if it is selected.

You opened your trunk lid and the mirror started dipping, you stopped, it stopped, you started again and it continued on.

This could be because the F125 switch is toast and you vibrated it some....it's stuck close to the reverse setting right now instead of the park setting. So you induce a little vibration into the car and it makes contact and breaks contact.

It has a lot of inputs from in including into the engine control unit.

I've read on other forums on Audiworld people having this multi function switch fail and it reeks havoc on many systems on their car.

Here's how you would go about replacing the switch:

Multi-function Transmission Range (TR) switch -F125-, replacing
Removing

- Remove left transmission support page 37-22 . Just unbolt it....no problem.

<img src="http://www.audipages.com/Tech_Articles/auto_transmission/transswitch1.gif">

- Disconnect multi-function TR switch -F125- from transmission and pull off of selector shaft.

<img src="http://www.audipages.com/Tech_Articles/auto_transmission/transswitch2.gif">


Installing

- Locate multi-function TR switch on selector shaft.
Flat section on gearing in switch -3- must come to rest on flat section of selector shaft -1-.

CAUTION!

Locate the multi-function TR switch -F125- on the center of the selector shaft.
Do not tilt the switch or push it on forcefully. Otherwise, the switch contacts may be damaged.

- Rotate switch until fitting hole -4- on switch housing can be located on fitting pin -2- on transmission housing.

Tightening torques

Component
Torque

Multi-function TR switch -F125- to transmission
8 Nm (71 in lb)

Transmission support to transmission
40 Nm (30 ft lb)

Transmission mount to subframe
40 Nm (30 ft lb)


I'm not saying this is your problem or that you should replace the switch....but you might want to call the dealer and see how much it is. Karpdiem just posted something today....you might be able to get a used one too.

I'm here in WI and know there is a yard with 3 A8s try them- Don's Sports Cars 920-779-6922. Good Luck.

I could troubleshoot this switch if I had your car, but we're three hours away!

pw

 

The wiring diagram designations are B108 "in wiring harness interior, right, rear" and 60 "near taillight, right".

If either ground is bad, trunk light voltage can go through the reverse lights to energize the mirror control, and reverse light voltage can go through the taillights to tell the instrument cluster that the parking lights are on.

This explains neither why the central console doesn't light up when you turn on the headlights nor why the check engine light came on. Those could be separate problems.

 

I'm too tired to look at it....but if what ttuling is saying is correct....sounds like a winner to me! Just have to find those connections. Look inside the rear corner of the car by removing the interior trim....see URL below on how to take out the inside right panel.

The ground connections will be a bunch of brown wires together attached the body chasis, inspect them and take the connection apart, clean and reinstall.<ul><li><a href="http://www.audipages.com/Tech_Articles/electrical_equipment/antennaremove.html">Removing the interior tunk trim</a></li></ul>

 

Do ttuling's solution first most likely dead on correct

 

Thanks for all the tips. The flu bug bit me last night so today I am not up to doing much work. However, I did notice walking into the Drs.office that in fact the mirror selector was set for the LEFT mirror! Freaky, isn't it?

I will try the ground thing tomorrow.

Thanks guys,

Sam

 

I hope you recover soon.

The mirror switch position doesn't invalidate the bad ground hypothesis: in the Left position, the mirror selector switch connects +12V from the switched X-wire to the mirror control module. In the Right position, it connects ground to the same control module wire. When the car is turned off, the X-wire is probably grounded well enough by some of the other loads attached to it that the Left switch position is read as Right by the control module when the car's off. Normally you'd never notice because voltage on the Reverse light supply wire is not supposed to be available with the car off.

If the switch had been in the middle -- not connected to anything -- then the mirror movement would have been inexplicable.

Tom